Dr. Sam Nabula noticed anecdotally that if he drank more water during the day he would sleep longer at night. He decided to test his observation on 12 of his students. The 12 "volunteers" reported their average water consumption and average number of hours of sleep per night. Their data is in the following table. Ounces of water Hours of sleep 28 9.5 68 7.75 128 4.5 54 9 72 7.5 62 8.25 59 8.75 110 5.5 84 5.75 64 8 116 5 76 6.5